1. Field of Invention
The field of invention relates generally to the transport of freight containers, and more particularly, to a system and process for improving container flow at a port facility, as well as improved equipment and/or software for use in such a facility.
2. Background Description
Freight containers have been used for many years to transport dry and refrigerated goods across the world's oceans, or land. For local land moves, metal containers, which may range in size from 20′ to 45′ and can carry loads ranging up to 85,000 lbs., are carried on trailer chassis which are towed by semi-tractors. For long distance land moves, the containers are stacked on flatbed railroad cars, which are pulled by diesel or electric locomotives. For water moves, the containers are stowed in specially designed holds and/or on the decks of barges or ships.
Port facilities, often measuring hundreds of acres in size, have been established at various places throughout the world to facilitate the transfer of the containers from one form of transportation to another. Some of the world's most famous ports include the terminals at Long Beach, Calif., New York, N.Y., Yantian, China, and Hong Kong. At each port, large quay cranes are strategically positioned along the quay line. Operating day and night, the quay cranes transport containers from land-based trucks and trains to the holds and/or decks of sea-going container ships. The quay cranes include an operator's booth and are operated by human operators who work hourly shifts. In operation, an empty train car or truck chassis is positioned beneath the quay crane's boom. A container is lifted from the container ship berthed against the quay and must be precisely maneuvered to engage the train car or truck chassis. Once the container is secured, the process repeats until the necessary unloading is complete. Alternatively, a ship-to-shore crane may lift a container from the ship and place the container on the ground. A straddle carrier, often positioned behind the quay crane, then hoists the container from the ground and loads the container onto a truck chassis or railroad car positioned beneath the straddle carrier. The processes described above operate in reverse to transfer containers borne by trucks and trains to the container ship.
The loading and unloading processes described above have several disadvantages. Human operators are prone to make mistakes, especially when tired. Further, picking a container from a train car or truck chassis, or lowering a container to the same, is difficult and time consuming even in the best of weather, but may be extremely difficult during inclement weather. In addition, the quay cranes tend not to be used to their fullest operating capacity because the time it takes to load or offload a train car or trailer chassis is longer than the time it takes to transfer a container from ship to shore or vice versa. Further, significant delays may be experienced if a truck or train malfunctions or is misdirected. In such instances, the quay crane cannot operate until another train or truck is properly positioned. This poses problems for the container ships, which are often in port only between tides. A delay in loading or unloading the container ship may result in the ship missing its scheduled departure time. In addition, the manual nature of container terminals sometimes results in the transfer of containers to/from ships to trucks being done in a chaotic manner. Consequently, the traffic flows are accident prone. Further, limitations in existing equipment limit the density of container stacks. This means it takes a large area of real estate to support a given level of container storage.
Thus, there is a need for an improved port facility, including improved equipment and software, that provides increased efficiency of operation and improved container flow.